It has long been customary to merchandise many products in tubes. Typical products packaged in tubes include toothpaste, lotion, caulking compound, etc. Currently, tube filling is generally performed by automated machinery. Rotary piston tube filling machines are probably the most common machinery now in use for filling tubes. Typical examples of rotary piston tube filling machines are shown in U.S. Pat. No. 2,958,346 and U.S. Pat. No. 3,825,043. Additionally, such machines are currently manufactured by Norden Packaging Machinery AB, Kalix Inc., Iwk Packaging Machinery, Inc. Pack. Dev. Co. Ltd. and Aktron, Inc.
A tube filling and sealing station made by the assignee of the present application, Innovation Automation Inc., is described in U.S. Pat. No. 5,209,044 to D'Addario et al., which is incorporated herein by reference. The apparatus of D'Addario et al. rapidly and efficiently fills tubes of various sizes and dimensions and avoids or minimizes the delays from inadvertent spills and misalignments that typically occur in a rapid tube filling operation. The apparatus is comprised of a rotating disc having a plurality of stations in which filling functions associated with the filling of tubes on a production basis occur. The disc is provided with a plurality holes in which tube filling support means are inserted to retain the tubes and enable simultaneous operations at a plurality of stations. The disc is provided with plastic collars at each hole to accommodate the tube support means for both rotation and secure placement. Work stations are provided in registry with the rotating disc and comprise a means for loading tubes into the tube holders, means for properly registering and determining registration and orientation of the tube for subsequent functions, reject means, cleaning means, filling means, sealing means, trimming means, and tube eject means.
FIG. 1 shows a prior art sealing device 2 marketed by AMTECH which may be used in the tube filling apparatus of the prior art. A filled but unsealed tube 4 is encased by a cylindrical tube support member 8 and moved into position for sealing via an indexing motor 6. An anvil 10 is positioned on one side of the unsealed tube 4 and a horn 12 is positioned on an opposite side of the unsealed tube 4 in an open position. The anvil 10 and horn 12 laterally move from the open position towards the tube 4 into a sealing position so as to pinch the tube end to be sealed against each other. The anvil 10 then remains stationary, and the horn 12 vibrates to emit a burst of ultrasonic energy to effect a seal of the tube end. The ultrasonic sound waves cause the molecules in the tube material to vibrate, drift together and solidify into the desired seal. The anvil 10 and horn 12 then retract away from the tube 4 to the open position after sealing. When the sealing process is complete, a sealing device computer 77 sends a signal to a main computer (not shown) to continue processing and to load the next open tube for sealing.
The molecular action of the ultrasonic sealing process generates heat energy which is dissipated from the inside of the seal out towards the anvil 10 and horn 12. When large tubes are ultrasonically sealed in accordance with this prior art method and apparatus, longer dwell times are required to effect a proper seal. As a result, it has been discovered that more heat is generated and undesirably transmitted back to the anvil 10 and horn 12. The excess heat changes the physical properties of the anvil 10 and horn 12 and causes the sealer to use excessive energy, which leads to an overload condition. Thus, it has been desired to cool the ultrasonic sealer already in use in the prior art tube filling stations in order to negate the effect of excessive heat generated from sealing large tubes.
In the prior art, the anvil 10 is cooled via a heat exchange medium such as externally cooled water which is transported through a number of passageways disposed through its body. This type of cooling may only be implemented on the anvil 10 since it remains fixed during the sealing process and does not vibrate to emit ultrasonic energy to effect the seal. The horn 12, however, cannot be cooled in this manner since the use of such a cooling means undesirably affects its ultrasonic vibration properties.
The simplest way to cool the horn 12 of the sealing device 2 is to intermittently stop or slow down the machine and allow it to cool. This is undesirable since it decreases the productivity from the filling apparatus. Another way to cool the horn 12 is to blow cool air over its surface and convectively cool it. This, however, only imparts minimal heat transfer and has not resulted in desirable cooling effectiveness.
It is thus an object of the present invention to provide an apparatus and method to effectively cool an ultrasonic sealing device which is already in use in an existing tube filling and sealing production line.
It is a further object of the present invention to provide an apparatus and method to effectively cool such an ultrasonic sealing device without slowing down or stopping the tube filling and sealing production line.
It is a further object of the present invention to provide an apparatus and method to effectively cool such an ultrasonic sealing device without adversely affecting the ultrasonic sealing properties of the device.
It is a further object of the present invention to provide an apparatus and method to effectively cool such an ultrasonic sealing device which overcomes the deficiencies of the prior art.